Question

Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process : 
Why is powdered coke sprinkled on top of the electrolyte? 

Answer 1

Coke while burning takes up oxygen from   Al₂ O₃ (bauxite) and is converted into Co and also into  CO₂ . 

• The CO produced also reduces Al₂ O₃ . This reduction process helps in purification of aluminium.